/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.log4j.helpers;

import org.apache.log4j.spi.AppenderAttachable;
import org.apache.log4j.spi.LoggingEvent;

import org.apache.log4j.Appender;

import java.util.Vector;
import java.util.Enumeration;

/**
 * A straightforward implementation of the {@link AppenderAttachable}
 * interface.
 *
 * @author Ceki G&uuml;lc&uuml;
 * @since version 0.9.1
 */
public class AppenderAttachableImpl implements AppenderAttachable {

    /**
     * Array of appenders.
     */
    protected Vector appenderList;

    /**
     * Attach an appender. If the appender is already in the list in
     * won't be added again.
     */
    public void addAppender(Appender newAppender) {
        // Null values for newAppender parameter are strictly forbidden.
        if (newAppender == null)
            return;

        if (appenderList == null) {
            appenderList = new Vector(1);
        }
        if (!appenderList.contains(newAppender))
            appenderList.addElement(newAppender);
    }

    /**
     * Call the <code>doAppend</code> method on all attached appenders.
     */
    public int appendLoopOnAppenders(LoggingEvent event) {
        int size = 0;
        Appender appender;

        if (appenderList != null) {
            size = appenderList.size();
            for (int i = 0; i < size; i++) {
                appender = (Appender) appenderList.elementAt(i);
                appender.doAppend(event);
            }
        }
        return size;
    }


    /**
     * Get all attached appenders as an Enumeration. If there are no
     * attached appenders <code>null</code> is returned.
     *
     * @return Enumeration An enumeration of attached appenders.
     */
    public Enumeration getAllAppenders() {
        if (appenderList == null)
            return null;
        else
            return appenderList.elements();
    }

    /**
     * Look for an attached appender named as <code>name</code>.
     *
     * <p>Return the appender with that name if in the list. Return null
     * otherwise.
     */
    public Appender getAppender(String name) {
        if (appenderList == null || name == null)
            return null;

        int size = appenderList.size();
        Appender appender;
        for (int i = 0; i < size; i++) {
            appender = (Appender) appenderList.elementAt(i);
            if (name.equals(appender.getName()))
                return appender;
        }
        return null;
    }


    /**
     * Returns <code>true</code> if the specified appender is in the
     * list of attached appenders, <code>false</code> otherwise.
     *
     * @since 1.2
     */
    public boolean isAttached(Appender appender) {
        if (appenderList == null || appender == null)
            return false;

        int size = appenderList.size();
        Appender a;
        for (int i = 0; i < size; i++) {
            a = (Appender) appenderList.elementAt(i);
            if (a == appender)
                return true;
        }
        return false;
    }


    /**
     * Remove and close all previously attached appenders.
     */
    public void removeAllAppenders() {
        if (appenderList != null) {
            int len = appenderList.size();
            for (int i = 0; i < len; i++) {
                Appender a = (Appender) appenderList.elementAt(i);
                a.close();
            }
            appenderList.removeAllElements();
            appenderList = null;
        }
    }


    /**
     * Remove the appender passed as parameter form the list of attached
     * appenders.
     */
    public void removeAppender(Appender appender) {
        if (appender == null || appenderList == null)
            return;
        appenderList.removeElement(appender);
    }


    /**
     * Remove the appender with the name passed as parameter form the
     * list of appenders.
     */
    public void removeAppender(String name) {
        if (name == null || appenderList == null) return;
        int size = appenderList.size();
        for (int i = 0; i < size; i++) {
            if (name.equals(((Appender) appenderList.elementAt(i)).getName())) {
                appenderList.removeElementAt(i);
                break;
            }
        }
    }

}
